This invention relates to an alarm condition sensor device adapted to be mounted on an object to be protected against burglary, theft, tampering, and the like. The sensor device is particularly adapted for use with an automotive vehicle, but its uses are virtually unlimited. The sensor is coupled to an alarm circuit and is operable to sense acts incidental to attempted burglary, theft, tampering, and the like and initiate the operation of an alarm signal. The sensor is sensitive to vibratory, inertial, and other motion forces applied directly to a vehicle or the like, but is relatively immune to the effects of passing vehicles, street noises, and the like.
Various sensing and triggering devices for vehicular and other alarm systems have been proposed heretofore, some of which have been responsive to vibration, movement, and other forces incidental to attempts to burglarize, tamper with, or move the vehicle. One of the undesirable characteristics of some of the known devices is the tendency to trigger the alarm falsely in response to the passage nearby of heavy vehicles or as a result of street noises and the like.
A principal object of the invention is to provide a vehicle alarm system and sensor therefor which overcomes the disadvantages of previously known systems and sensors.